Treatment of mineral absorbent material



De. 17, 1935. G, R LEWERS 2,024,589

TREATMENT OF MINERAL ABSORBENT MATERIAL Original Filed May 15, 1929 2SheetS-Sheet v1 54 fontfamily 01'! llceoam Z7 INV ENToR eorge i?.Len/ers Z9 BY had W `AT ORNEYS G. R. LEWERS INERAL ABSORBENT MATERIALTREATMENT 0F M Original Filed May 15, 1929 2 Sheets-Sheet 2 vINVENTOReorg RLeWers BY Patente-d Dec. 1.1', 193s UNITED STATES PATENT r OFFICE.

rliEATlvmNr F MINERAL ABSORBENT MATERIAL poration of DelawareApplication May 15, 1929,` Serial No. 363,154 Renewed Gctober 19, 1934 v'z claims. (01. 20a-104) This invention relates to the treatment of min-"embodiments of Y`which are described herein by eral absorbent materialsafter the been used for the treatment of oil, to recover oil Atherefromand to reactivate said materials. A division of this application Ser.No. 23,350, filed May 25, 1 935, relates to the refining of oil by the"use of mineral absorbentmaterials and the re- Vcovery of oil from suchmaterial in connection with the refining steps,

A process' has been heretofore proposed for car,

rying out such refining, but the amount of earth that may be used in iti`s limited on account of the type of apparatus employed and this hasresulted in the production of oil which still rel5 tainedsubstancesgivin'g it an undesirable color. This prior proposed treatmentalso employed a cumbersome and expensive method for removing the oilcontent from the earth after that content had been reducedto about 30%more or less.

- mass in the open air wasd dangerous because of the possibility ofexplosion of the solvent if it were ignited by a spark or otherwise.

The process and apparatus hereinafter disclosed and as claimed in mysaiddivisional application provide for eiciently doing away with thedisadvantages noted in the -above mentioned proposed process, and `atthe same time may' be opj erated rapidly and- .continuously to produce ahigh yield of substantially entirely decolorized 40 oil,- if desired;with a minimum fire hazard. The

objects of the invention claimed herein, include the provision of asimple eiiicient apparatus. and

' method for the treatment of the earth for removal of the oil contentvand reactivation of the sdearth, afterlits use for the .treatment ofoil.

` Further and more specific objects, features and advantages willclearly appear `from theA detailed description given below taken inconnection with the accompanying drawings which form a part 5o of thisspecification and illustrate, by way of' example, embodiments of theAinvention.l Y

The invention accordingly comprises the novel apparatus and combinationsthereof, as well as the novel processes and' steps of processes which vmay .be carried out ,in such apparatus, specic same have with a suitableagitator and as I prefer to carry way of example only and in accordancewith the manner in which I now prefer to practice the inthe process fromthe initial combination of crude oil and earth through to theproduction-of a' cake containing oil which is to be'further treatedforremoval of this oil prior to reactivation;

Fig.v 2 is a diagrammatic illustration of the l0 arrangement ofapparatus which may replace .the devices shown in the latter half of theflow sheet of Fig. 1, that is from that part of the flow sheet where theagitator `with steam coils is shown through to the end of the flowsheet; y 1:5'

Fr 3 is` an elevation partly in s'ection of a Herrescho furnace withmufde furnace mounted on' top thereof for receiving the filter cakecontaining oil;

Fig. 4 is a cross section on the line 4,-4 of Fig. 20 3 on a reducedscale;

Fig. d is a sectional detail vview taken on the line 5-5 of Fig. 3showing the rotating valve for discharging the cake; -and Fig. 6 isafragmentary sectional view showing 25 the use of stuffing boxes insteadof a mercury seal around the main shaft shown in Fig. -3. 4

In .carrying Aout the process as shown in the flow sheet of Fig. i, Imix crude oil with a suit.- able proportion of earth in finely dividedform such as Filtrol, ground fullers earthfor the like, preferably of aneness sothat will pass a 200 mesh sieve. The crude oil and earth'aremixed in a vapor-tight mixing tank I provided out my process, the oiland earth are supplied continuously to this tank and the mixture isdrawn off and allowed'to flow through a tube or other still and filterarranged in cascade, placed so that the flow is by gravity therethrough.'Ihe oil and earth ow to a tube or still 2 in which they are heated to asuflicient temperature to cause decolorization to occur. Thistemperature v will vary somewhat'but Ihave found that with A the crudeoil from the Mid-.Continent and Penn- 45 'sylvania Districts with thelimits of 80 to 120. `parts of oil to 7 5`parts .of nely ground Filtrol,the temperature of 230 `C. to 350 C. will cause gravity to an OliverorLaughlin filter 3 or otherv 55 type of continuous filter or centrifugefrom which the cake passes to a conveyor and the decolorized importantbecause if a smaller amount of earth is used a corresponding decrease inthe amount of color removed from the oil occurs. I prefer to remove asmuch color as possible from the oil and I accordingly prefer to employthe earth within the limits mentioned. Heretofore the proportion ofearth employed has been considerably below' these limits and the mixtureof oil and earth has been handled by pumps and after the mixture hasleft the still it has been passed around through a heat-exchanger togive up the heat acquired from the still to the oil entering the stilland thereafter has passed to the Oliver filter. I have found, however,that in using a larger proportion of earth that the mixture cannot besatisfactorily pumped in this manner and that if attempt islmade to passit through a heat-exchanger it clogs the' interior and properheat-exchange is not effected. I have found, however, in accordance withmy inve'ntion that, even with thelarge proportion of earth employed forcomplete decolorization, the mixture will still pass through pipes andthrough the apparatus employed by gravity as long as the system issufficiently cascaded to give a head to the mixture" so that it williiow evenly and at the desired 'ratetherethrough The cake coming fromthe filteron to the conveyor contains approximately from 20 to 30% ofoil which is to be recovered. I have found that the recovery of this oilfrom the cake can be done" bydry distillation but I find that materialsuch as Filtrol and similar earths apparently act catalytlcally on theoil when it is heated, as in the process of distillation, to crack. theoil and thus break down valuable constituents such as lubricating oilstherein with consequent depreciation of the value of the productsrecovered by such distilling process. I therefore prefer to recoverthese oils by other means, which avoid to a large extent the crackingreferred to. l

It has been proposed in the `vpast, as noted above, to take this oilcake and place it in an expensive still in batches of 5 to.6 tons heldin internal filters in which it was treated with a highly inflammablevolatile solvent, with which it was agitated for from 30 to 60 minutesand allowed to settle for a period ranging from 14 to 22 hours duringwhich period decanting occurred and at the end of which period the cakecontaining a proportion of oil and of the solvent dropped out into theair and from there was taken to the Instead of such an apparatus andprocess, I

rprefer to deliver the cake containing 20 to 30% of oil from a conveyor4 into a vapor-tight agi- .tator l provided with a series of steamcoils.

The cake is there agitated with solvent at a temreactiyating plant.Thereafter another batcl'iY course controlled by the rate o'fintroduction perature of about 30 C. to 50 C. Coming from the lastcontinuous vapor-tight filter 1 provided with steam jacket or coils 'la'shown in Fig. 1,

being pumped through pump 8 and line 9 to the agitator 5. This solventcontains some oil and 5 is continuously fed to the agitator in Ydesiredproportion to remove oil from the cake which is continuously fed fromthe conveyor 4 to'the agitator. The amount of solvent will vary with thepercentage of oil in the cake. I have found that with a ycake containing20 to 30% oil that the solvent should be present in the agitator to theextent of one part of the cake by weight to about one part of solvent.'Ihe rate of supply is of of new solvent which occurs at a later stagein the process.

After agitation of the solvent andv cake the mixture passes to avapor-tight continuous filter or centrifuge I0, provided withsteamjacket, coils or both Illa, the solvent removed by this means beingpassed to a positive filter such as a Dorco filter or blotter presswhere remaining traces of the clay are taken out which may be collectedandvreturned from time to time to the agitator 5. The solvent plus oilthen goes to a recovery tank 6.

The cake coming from the lter i0 passes by 'a conveyor Il provided witha steam jacket or coils Ha, to a second vapor-tight agitator I2 30'where new solvent is added through a line I3 at a desired rate asmentioned above, the cake and .solvent being maintained at 30 to 50 C.by

steam coils within the agitator i2. The cake being continuously suppliedby the conveyor il 35 to the agitator is mixed with new solvent andcontinuously passes to the continuous filter' or centrifuge 1 where thesolvent containing oil is separated and passes back through the pump 8and line 9 to the agitator 5. The cake passes 4o to the furnace througha conveyor I4 provided with steam coils or steam jacket Ma. The steamjackets or coils Illa, Ila, 'la and Ila are provided in order to applyheat to the materials which are being acted on bythe continuous filteror centrifuge I li, conveyor II, kcontinuous filter or centrifuge 'l andconveyor I4 respectively. The steam entering thesejackets or coils willordinarily be at 120 lbs. pressure approximately, while oilslsuch asherein mentioned are being treated. By the use of air or mercury insteadl of steam, higher temperature may be'secured if desired.

The action of these steam jackets or coils is to drive off from themixture of clay and oil, some of the oil which5 is volatile at thetemperature provided by the steam or other medium employed.

` The .oil vapor thus produced is taken off by pipes |0b, Hb, 1b and Mbrespectively .from the continuous filter or centrifuge I0, conveyor Il,ccntinuous filter or coil 1 and conveyor I I. As shown the pipes'l alllead to the solvent line 9 Where the vapors combine with the solvent andpass into the agitator 5. Instead of or supplementing the steam ccils,steam--as live, exhaust or superheated steammay be introduced int'o theinterior of the cylinder of `the filters I0 and 1 and into conveyors Ilandv I4. Any .condensed steam in the yinterior ofthe cylinder of filterI0 will pass to the recovery tank and the condensed water may bedrawn'off. Steam passing into the vapor lines Mib, Hb, 'lb'and .Hb willeventually find its way to the recovery tank and be removed. 'Ihe newsolvent which 'I prefer to introduce .through the pipe Il, is a blendingnaptha havu ing about the following characteristics-specific gravity' 62(A. P. I.); ilnal boiling point 400 F.; initial boiling point`90-100 F.I prefer to have a naptha which has a boiling point for a largeproportion thereof at an intermediate range between 100 land 400 F., andthe less the amount of oil distilling at the lowest and highest figuresofthe range, the better. I may also use, if I desire; solvent which ismore volatile than the above blending naptha, but in general suchsolvents are apt to be more expensive and losses thereof arecorrespondingly more expensive 'in the operation of the process. I canuse for example as solvent a petroleum distillate having a specicgravity of 68.3 (A. P. I.), initial boiling point 140 F., flnal boilingpoint 212 F. and containing less than 2%' aromatics.

Instead of the separate agitator and steam coils and continuous filter,these pieces of appa.-

ratus may be combined into single units as shown H in Fig. 2 forcarrying out' the process. When so combined the continuousiilter I5 iscased'in the vapor-tight housing I6 in the lower part of which laresteam coils I1 and two sets of agtators I8.

The cake containing to 30% oil is fed in from a conveyor through theconveyor I9 and is. there agitated with solvent containing some oilcoming from thelter 20 ofthe second stage of the proc- 1ess' andconveyed through the pump 2I in line 22 to the housing I6.r A branchline 23 feeds the solvent containing oil on to the cylinder I5 servingto wash the cake thereon. The cake from the cylinder I5 is scraped oifby scraper 24, passed to a conveyor 25 which delivers it through pipe 26to the vapor-tight housing 21 around the filter 20. 'I'his housing issimilarly provided with steam coils 23 and agitators29. The cake formedis scraped off by a scraper and removed by -a .cake normally containsapproximately 1% or more of oil, the remaining 99% having been taken outby the processes so far mentioned. This cake passes by pipe '34in eachofFlgs. 1 and 2 through a rotary valve whichV will be described below onto a hearth of a distilling mullie furnace which is suitably heatedtoab'out 300 C. and

from which the remainder of the oil and any solvent are driven off bydistilling through a pipe 36 andrecovered. i

Instead of extracting oil from the cake coming from conveyor 4, bytreatment withl solvent as indicated, the cake containing 20 to 30% oilmay be placed directly inthe mufile furnace and distillation of the oileffected, but by this means the oil remaining in the cake is notrecoveredas it is in the process using agitation and filtering asdescribed. Instead the oil tends to break down on heating in thepresence of the clay, as previously mentioned, and to produce somewhatless desirable distillation products.

After treatment in the muiiie furnace, the cake substantially free fromoil and solvent is then passed through a rotary valve similar to the oneto the entrance of the muille furnace on to the top hearth of a. rotarymultiple hearth Herreschoff furnace such as described in the patent toD.

Baird No. 1,375,346. In passing through the multiple hearth furnace, thematerial is reactivated by being brought into contact with highly heatedair which causes lcombustion of the carbonaceous matter other than theoil and solvent still re- 5 maining in the clay thereby causingreactivation of the clay to occur. 'I'he clay then descends to thebottom of the furnace and is removed through a suitable exit and is thenready for use again starting at the first part of the process as shownat the top of the flow sheet in Fig. 1.

Referring now to Figs. 3 and 4 on top of a multiple hearthlfurnace'designated as' 31 preferably of the Herreschoif type, althoughother types of amultiple hearth furnace may be employed, is 15 mountedthe munie furnace 35 which is circular in form and of substantially thesame diameter as the Herreschof furnace. This furnace is heated by anannular flue 38 of carborendum or other suitable fire-resistant materialwhich lies 20V on the outer edge of the floor of the furnace. An oilburner 39 projects into the flue 38 and the V rodcts of combustiontherefrom on ctheirV way o the e'xit flue 40 heat the material in the :nuiiie l furnace. '25 The rotary valve for supplying material from pipe34 to th hearth of the furnace is shown more clearly in Fig. 5. Itcomprises a casing 4I substantially cylindrical in form and tightlyfitting within the casing a cylinder 42 having a rec- 30 tangularopening 43 forming lthe mouthof a chamber of about the cross-sectionaldimensions of the opening, having-a depth of the diameter of the casingand lying transverse to the axis thereof. When the opening is incommunication `35 with pipe 34 the chamber may 'be lled. This sameopening permits the discharge of the chamber when it is rotated through180 sothat it is in communication with a pipe 44 therebelow which isslightly flared and which is fastened to the roof of the furnace 35 andcommunicates byl an opening therethrough with the interior of lthefurnace. The cylinder vis rotatedat suitable intervals to receive chargefromI the pipe 34 and to discharge it into the muiile furnace by means45 of a shaft 44a which is rotated by an outside source of power notshown. In view of the tight iitlof the cylinderl in the casing andexclusion of air from the cylinder when. it is full of the cakedischarged into it through pipe 34, no air is admitted into the muiilewhen the cake is discharged through pipe 45 into it. It is importantthat air be excluded in order` to avoid burning of cil entering themuiile. The usual central shaft of the multiple-hearth furnace 46 isextended 55 upwardly through the muiile furnace and carries on it an arm59 of the usual type by winch material in the munie furnace is agitatedand finally moved to the exit pipe 48 in the floor of the mufiiefurnace. This exit also has an air-tight 60 value associated with it sothat material can be dumped from the muille furnace on to the upperhearth 41 of the multiple-hearth furnace. This rotatingfvalve is'identical as' here shown with that shown in Fig. 5. i In order toprovide an air-tight seal between the shaft 46 and the upper and lowerwalls of the muiile furnace through which it passes, waterccoled mercuryseals 50 and 5I are placed respectively about the shaft where it entersthe upper and lower walls. Instead of'the mercury seal as shown in Fig.6 ordinary stuiling boxes 5 2 and 53 may be used respectively forpreventing the admission of air to the inutile furnace.

Vlin the .roof 54 of the multiple-hearth-fur- 75 nace an exit for heatedgases passing'through the furnace .is provided and designated 55. Theexit for these gases is preferably placed as indicated so that the gasesmay serve for the heating of the bottom of the muliie furnace passingthrough the space between the roof 54 of the multiple-hearth furnace andthe bottom wall of the mufile furnace, and then out through an exit 56.In order that the amount of heat supplied to the bottom of the muillefurnace in this way may be regulated, a flue 51 is provided in theextension of the side wall 58 of the muillefurnace by which the furnaceis supported on top of the Herreschoif furnace. By opening this flue,air may be admitted to cool the gases of combustion passing through thespace between theu muiile and the multiple-hearth furnace.

In operation the apparatus shown in Figs. 3 to 6 is as followsz-Materialis fed through the pipe 34 to the hollow cylinder 42 rotating anddischarging` at intervals into the interior of the mufe furnace. 'I'heoil burner 39 havingbeen previously started to heat the muiile furnace,the latter heats the charge on the floor thereof and drives off the oilremaining in the cake fed through 34. This oil passes off to a suitablerecovery apparatus. rIhe shaft 46 having been put in motion, the arm 59passes material to the exit 48 through which it is delivered by therotating valve connected therewith on to the hearth 41 of theHerreschoff furnace, from which it is raked in the usual manner throughthe multiple-hearth structure to an exit at the bottom. In first.starting up the furnace, torches are applied to bring it up to heat andthereafter air admitted through air inlet port 58 in the usual mannerinto the interior of the furnace through controlled air openings causescombustion of the carbonaceous material still retained in the cake,thereby supl plying suiicient heat to maintain the temperature of freshcake falling to the hearths at a high enough point to continuecombustion.

p The process and apparatus described are simple and eicient. Theyfunction continuously and rapidly and hence are adapted to handle largequantities of material vWithin a short period. 'Ihere is a minimumfire-hazard due in part to the use of less inflammable solvents than arerequired in the prior process described above and in part to thehandling of material containing inflammable oil in vapor-tight chambersto avoid such combustion. The avoidance of such com--V bustion not onlyminimizesthe hre-hazard, but also saves loss of such combustiblematerials. An oil may be recovered by this treatment having asubstantially water-white purity.

The term earth as herein used is intended to include fuller's earth,diatomaceous earths, such as kieselguhr, Filtrol, and similar materialslused for the treatment of oil.

While.I havedescribed my improvements in detail and with respect topreferred forms thereof, I do not desire to be limited to such detailsor forms, since many changes and modifications may be made and theimprovements embodied -in widely different forms without departing fromthe spirit and scope of the invention in its broader aspects. HenceIdesire to cover all modifications and forms coming within the languageor scope of any one or more of the appended claims. fj

What I claim is: 1. Ina furnace of the character described, in

- combination, a multiple hearth oombustion'furnace comprising a seriesof superposed hearths for series flow of solid material from one to an-'liberating'oil distilled from cake containing oil other, asubstantially air tight munie furnace above the multiple hearth furnace,a, vertically arranged shaft passing centrally through both the multiplehearth and mufile furnaces, rabble arms for the hearths of thecombustion furnace and for the muiile furnace, carried by the shaft, twovalved means, substantially gas tight, for admitting material into themutile furnace and for discharging it from the muiile furnace onto theuppermost hearth of the combustion furnace, a partition spaced below thefloor of the munie furnace and forming a top for the combustion furnace,a chamber just below the floor of the muille furnace, the bottom of themuiile furnace forming the top of said chamber and said partitionforming the bottom of said chamber, the partition being for the mostpart imperforate but provided wth.at least one opening for the passageof hot gas into said chamber, and separate gas exits from the mufilefurnace and said 20 chamber.

2. In a, furnace of the character described, in combination, a multiplehearth combustion furnace comprising a series of superposed hearths forseries flow of solid material from one to an- 25 other, a substantiallyair tight muifle furnace .spaced below themultiple hearth furnace, achamber defined between and by the floor of the muille furnace and thetop of the combustion furnace, means for conveying gas from theuppermost hearth of the combustion furnace into said chamber, acontrollable air inlet for the direct admission of cooling air to said4chamber for preventing .overheating of the floor of the n,

muilie furnace, a vertically and centrally arranged "D shaft passingthrough both the multiple hearth and muiile furnaces, rabble arms forthe hearths cf the combustion furnace and for the muie "furnace, carriedby the shaft, two valved means,

substantially gas tight, for admitting material 40 into the muillefurnace and for discharging it from the muiiie furnace onto theuppermost hearth of the combustion furnace, and separate gas exits fromthe muile furnace and from said 45 lfurnace and. said chamber.

4. In an apparatus of the kind described, in combination, a multiplehearth combustion furnace containing a series of superposed hearths forseries flow of solid material from one to another mounted about arotatable shaft, a substantially air-tight muiile furnace on top o1 saidmultiple hearth furnace comprising a device for heating said mui'ilefurnace, valves for admitting and discharging material respectively intoand from said muflie furnace While substantially excluding airtherefrom, a stirrer arm on said shaft for stirring the material chargedinto said muiile furnace, an exit from said munie furnace for chargedthereinto,land a device for heating the bottom of said munie-furnace bygases passing from said multiple hearth furnace along the bottom of saidmunie furnace.

' 5. Apparatus for the treatment of mineral absorbent material,comprising in combination, a

distilling muiile furnace for heating a mixture containing oil and spentmineral absorbent material, a combustion furnace'for burning'combustible material remaining insaid mixture and located below saiddistilling muiiie furnace, anA exit pipe for conveying distillate fromsaid muiiie furnace, means for introducing said' mixture in said muiliefurnace and for conveying the mixture from said muiile furnace into saidcombustion furnace, said means having an air-tight connection with thewalls of fsaid muiile furnace in its receiving, delivering andintermediate positions, rabbling arms for stirring the mixture in saidmunie furnace and in said combustion furnace, a common shaft extendingthrough the walls of said munie furnace for supporting and operatingsaid rabbling arms, an air-tight connection between said shaft and thewalls of said muiiie furnace,

a partition arranged between said muiile and combustion furnaces andforming a heating chamber Y with the bottom wall of said muilie furnace,said partition being perforated whereby gases of combustion may beadmitted to said chamber from porize the oil from the earth -withoutsubstantial cracking of the oil, maintaining said zone sumoil,withdrawing from said zone the oil as lthus distilled fromthe earth',substantially continui ously passing the earth after it is thus largelyfreed of oil, from said zone into a second heated zone substantiallyisolated against the passage of gases therefrom to said first mentionedzone. vand vgradually advancing the nely divided earth as a'layerthrough said second zone while agitatmg the same in the presence of astream of oxidizing gas, at a temperature causingcombustion of c saidcarbonaceous matter and reactivation of the earth.

7. A process for recovering oil from finely divided absorbent earthcontainingoil and' other 15 carbonaceous matter resulting from 'the useof the earth for the treatment of oil, and reactivating said earth,which consists in substantially continuously introducing said earth intoa distilling zone, gradually advancing the .earth as 20 a layer throughsaid zone while agitating l the same, heating said zone toy atemperature in the .neighborhood of 300 C. to vaporlze the oilfrom theearth, maintaining said zone sufficiently free of air to avoidcombustion of said oil, withdraw- 25 ing from said zone the oil as thusdistilled from the earth, substantially continuously passingthe Yearthafter it is thus largely freed of oil, from said zone into a secondheated zone substantially lisolated against the passage of'gasestherefrom $0 to said rst mentioned zone, gradually advancing -the finelydivided earth as a layer through said secondf'zone while agitating thesame in the lires-V ence of a stream of oxidizing gas, at a temperaturevcausing combustion of said carbonaceous 8 5 matter and reactivation ofthe earth, and utilizing heat from such combustion to heat said rstnamed zone.

i ciently free of air to avoid combustionof said GEORGE R.

